This proposal is to request support for a Keystone Symposia meeting entitled "Emerging Tumor Suppressors", organized by Kun-Liang Guan, Eric R. Fearon and Stephen H. Friend, which will be held in Taos, New Mexico from January 25 30, 2009. This symposium will cover the recent exciting discoveries on tumor suppressors and related areas. The sessions, topics, and speakers have been chosen to reflect the fact that cancers arise from multiple defects in tumor suppressor pathways and networks. The pathways to be discussed at the meeting are among those most commonly altered in cancer cells, and where exciting results have emerged over the past few years and where considerable progress is expected. The talks will offer exciting new results from the speakers'laboratories and it is expected that common biological themes will emerge in many sessions, such as the pleiotropic effects of tumor suppressor gene defects on multiple different cell phenotypes, and the likely cross-talk between tumor suppressor gene pathways that currently appear to be functionally distinct.